Alternative 3 is a television programme, broadcast once only in the United Kingdom in 1977, and later broadcast in Australia, Canada, and New Zealand, as a fictional hoax, an heir to Orson Welles' radio production of The War of the Worlds. Purporting to be an investigation into the UK's contemporary "brain drain", Alternative 3 uncovered a plan to make the Moon and Mars habitable in the event of climate change and a terminal environmental catastrophe on Earth.

The programme was originally meant to be broadcast on April Fools Day, 1977. While its broadcast was delayed until June by industrial action, the credits explicitly date the film to April 1. Alternative 3 ended with credits for the actors involved in the production and featured interviews with a fictitious American astronaut.